Low-friction variable pulley disk mounting



June 2, 1953 J, s, M|CH|E 2,640,365

LOW-FRICTION VARIABLE PULLEY DISK MOUNTING Filed NOV. 18, 1949 ngelzo T-.

IN VEN TOR.

dbHN S. MCHJE,

Patented June 2, l1953 .LQWJRICTION `VARI MQUN ABBE @UILEYI DISK `lohn S, Mlchia, Columbus 1nd assigner .t'o Reeves Pulley Company, Columbus, Ind., aA vcorporation'of'indiana spplieationnevember 1s, 1949, `serial1-m.,12s;14n

The-,presentinvention relates'to allow-friction variable pulley disc `mounting, and isjprixn'arily concerned with the provision of means. whereby `an element, mounted on a shaft for'axia'l reciprocation relative thereto`but rotationally `drivingly `'connected theretamay be supported'on said shaft to move freely in an axial direction `with a mini mum of frictional resistance and with` a "minlmum requirement forlubrication The invention ispartcularly applicable tothe imounting ofthe shiftable elements o f expansible V=pul1eys used in the well Aknown Reeves`type of variable speed power transmissions. 'In such an organization, 'two 'mating coned 'discs 'c0- operate withan edge-active friction'belt. Eachl of those discs Ymust be'rotationally fixed with respect to "theshaft upon which the'pulley is supported, but one or 'both of'said discsmust be laxially movablerelativeito the'shaft in order Ato vary the distance between the'apices of -said discs, Vthereby varying the depth `of 'penetration of the belt between the discs, and so lvarying the effective lpitch diameter 'of the-pulley. It is essential that there shall be no rotationalslipbetween the two discs, orbetween the discs andtheshaft; .and it isessentialthat the discs shall `bernaintained in absolute axial alignment withoutany substantial cantiner of 'either disc. Yet l'freedom' of `relative axial `movement between -the discs "is essential, since'sticking'of `anymovable disc will, of course, interfere kwith accurateland sensitive 'adjustment of the transmission.

Obviously, in order to guardagainst cantingyo'f a disc, a bearing engagement of-substantiallength must be'provided between the disc and the shaft. Additionally, in order to guard against any relative rotational movement between the two discs, which would, of eoursaresultin lserious "attrition upon the active 'edges of the belt, vit is essential that the means providing a drivingeonn'eotion betweenfthe shaft andthe discs'shall befperipherally tight-tting. Because of thesetwo requirements, a splined connection between theshaft and the discs'h'as heretoforebeen found'not' altogether satisfactory, since a -splinedconnection long enough to guard lagainst disc canting and tight enough to guard'against-relative rotational movement between the-discs involves van areaof frictional engagement between thesh'aft Aand `the discsV so great as'to preventthat freedom of axial movement ofthe discs'relative tothe shaft'which is essential to satisfactory operation Vof a transmission of the character .under consideration. Additionally, .suchla silined connections-'involves problems -of -lubrication which are substantially (Cl. I4-42,3017) insoluble, particularly where-y the unit is to lbe used` 'in an .environmentsuch that lubrication dippage must be prevented,

Consequently, the .arthas .consistently turnedto 'the use of keyed vconnections between the shaft vand 'the discs.; with all of the attendant disadvantages .of-such a connection. VWhile the keyed connection 'doesnob to an optimum degree, either satisfy the yrequirements of 'the unit .or overcome 'the .problem oi lubricationV and elieariliness, Vithas been necessary'to compromise'upon sucha connection, for 'lack of any .satisfactory solution of the problem,

According 'to .the present invention, .a mounting means, including a splined :connectionbe- 'tweenthe disc and the Yslrafaand'an antifriction mounting ofthe disc upon the shaft, .has 'been provided, yof such character as to satisfy "all Aof the 4above requirements,A while necessitating a 'minimum Vamount 'of lubrication. The 'structure adopted for the accomplishment of `those ob- Ijectives inicludes Va '.ball. `bushing o'f "substantial laxial length. interposedbetween'a shaft andal disc to be mounted "thereon, and'supported upon the (shaft, together with a spline wheel, fixed to the disc and ythebushinef, and meshing with ra vsplined "portion of vthe shaft. The ball bushing., known prior "to, my invention as va -unit capable `of free relative'axial movement upon a' shaft, has always been vconsidered as a, `unit incapable of use in anenvironment in which lit must lbe rotationally 'fixed vto the shaft; and a'major feature of'my invention is the recognition ofthe adaptability ofsucha yunitto anfenvironmentin v'which vthe ball bushing is rotationally fixed vwith respect lto the shaft upon which it is "axially free 'to move.

Further features Iand objects-'of the invention-will appear as lthe description proceeds.

To the acczson'iplishment of the above and related/objects, my invention vmay be embodided in the {form illustrated in the accompanying Vdrawings, vattention 'being called to the -fact, however, that the drawings are illustrative Nonly, and that changes lmay be made in the specific construction illustrated land described, so long as the. scope of the appended claims is not violated.

41l isv amore vorless diagrammaticplan view O f kOne 'ferm df variable speed transmission in whichmy invention iinds utility;

Fig. -2 :isan enlarged transverse section taken substantially on the line 2--2`of Fig.. L;

Fig. 3 is a broken end elevation, taken lfrom theLrightend-bfsFig. 2;.

Fig. Aeis `a vfurther enlarged lfrasmentaryaxal 3 section, showing details of the mounting of the present invention;

Fig. 5 is a transverse section taken substantially on the line 5-5 of Fig. 4; and

Fig. 6 is a broken perspective View of the ball bushing employed in my invention and its mounting upon a splined shaft section,

Referring more particularly to the drawings, it will be seen that I have illustrated, more or less diagrammatically, a Reeves variable speed transmission, indicated generally by the reference numeral Ill and comprising a frame II in which are journalled an input shaft I2 and an output shaft I3. an expansible V-pulley I4 comprising the discs I5 and I6; While the output shaft carries an expansible V-pulley I1 comprising the discs I8 and I9. An edge-active belt 20 is trained over theA two pulleys I4 and I'I to provide a driving connection therebetween. A lever '2I, pivotally mounted at 22, operatively engages anti-friction thrust bear,- ings associated with the discs E5 and I9, while a similar lever 23, pivctally mounted at 25, operatively engages similar thrust bearings associated with the discs I3 and i3. Nuts 2| and 2S', connected to the levers 2l and 23 respectively, are threadedly engaged upon oppositely threaded portions of an adjusting screw 25 journalled in the frame I I. As is well understood inthe art, rotation of the hand wheel in one direction will move the nuts 2I and 23' toward each other to separate the discs I5 and I6 and to move the discs I3 and I9 toward each other, thereby decreasing the speed of the shaft I3 relative to that of the shaft I2, while rotation of the hand wheel in the opposite direction will produce an opposite movement cf the said discs to increase the speed of the shaft Thus far, theV construction is conventional. According to the present invention, the mid-por'- tion of each shaft I2 and I3 Will be formed to provide a splined section 28 comprising a peripheral series of axially extending spline teeth 29 separated or defined by longitudinally extending grooves 33. The disc I8, for instance, is provided with an axially elongated hub 3I retreating from the apex of its coned face, and provided with an axial bore 32 somewhat larger in diameter than the spline teeth 29. Within the bore 32 of the hub 3l is snugly received a ball bushing indicated generally 4by the reference numeral 33, and to be described in detail hereinafter. As shown, the bushing 33 abuts, at one end, a. snap ring 35 re.- ceived in a suitable groove34 in the hub 3| vand a spline ring 35, having a peripheral series of teeth 31 received in the grooves 3B between the teeth 29, is xed to the rear end of the hub 3I as, for instance, by a seriesA of screws 38.- Said ring is provided with an axial projection 39 which abuts the rear end of the bearing 33, whereby said bearing is axially fixed with respect to the disc hub 3|. The conventional anti-friction thrust bearing 40 is suitably mounted upon the hub 3| for engagement by, for instance, the lever 23.

The bearing 33 comprises a carrier 4I formed to provide a peripheral series of round trackways 42. In each trackway is carried a continuous series of balls 43. An outer shell or housing 44 non-rotatively surrounds the carrier 4I, and closure rings 45, with which may be associated felt wiper rings 45', retain the carrier'4l in fixed axi ial association with the shell 44. ,Y

Each trackway includes an axially-extending rectilinear portion 46 radially opening both in- The shaft I2 carries, within the frame,.

Wardly and outwardly to an extent sufficient to permit the balls 43 currently located therein to project slightly beyond the inner periphery of the carrier 4I and beyond the outer periphery thereof. Each trackway further comprises a rectilinear, axially extending portion 4'I peripherally spaced from the section 46 and so constructed and designed as to lift the balls in that section radially outwardly so that such balls do not project beyond the inner periphery of the carrier, but do project, to a greater degree, beyond the outer periphery thereof. The inner periphery of the shell 44 is formed with longitudinally extending grooves 48 registering with the trackway sections 41, so that the balls 43, currently located in each trackway 41, project freely into such grooves 48. At their axially opposite ends,

i the trackway sections 46 and 41 are joined by part-circular sections, as shown, so that the series of balls in only one trackway may roll continuously,l in eitherv direction, round and round the trackway. It will be clear that the projection of the balls located in the trackway sections 4'I into the grooves 8 will hold the shell 44 and carrier 4l against relative rotational movement, although, in the environment in which the bushing is shown in the present disclosure, those elements are not subjected to any forces tending to produce such rotation, since the shaft I3 and the disc hub 3I, respectively engaging the parts of the bushing, are held against relative rotational movement by the spline ring 36.

The parts are so assembled that the balls located in each trackway section 45 register with, and are supported upon, the outermost surface of a spline tooth 29, while the balls located in each trackway section 4l register with `a spline groove 30. The relatively long series of balls in the trackway sections 45 provide a sufliciently long bearing upon the spline teeth 29 to obviate the possibility of canting of the disc, relative to the shaft. It will be noted that the spline teeth 31 are axially very short, whereby the total area of frictional contact between said spline teeth 3'I and the teeth 29 is not greater than would be the total area of frictional engagement in a keyed construction of conventional character. Because the bushing 3.3 `sufficiently guards against canting, the spline teeth 3l need not engage the bote toms of the grooves 39, and the spline teeth 29 need not engage the bottoms of the spaces between the teeth 3l.

In practice, ithas been found that, sincesix bearing lines can be provided in each hub, the length of each disc hub may be reduced, as com-f pared to conventional keyed construction, thereby improving the compactness of the entire unit as compared to conventional construction.

In the illustrated embodimentV of the invention, the disc I9 is similarly mounted on the shaft I3, being provided with a hub 9 in which is received a bushing 50 identical in construction to the bushing 33, and held in place in the hub between a snap ring 5I and a spline ring 52 suitably secured to the free end of the hub 49 and provided with spline teeth 53. A conventional anti-friction thrust bearing 54 is mounted on the hub 49 for engagement by the lever 2 I.

The pulley I4 will be constructed in a similar fashion, the hubs of its discs I5 and I6 being supported on a splinedsection of the shaft I2 through ball bushings like 33 and 50 and similar spline rings. While the illustrated arrangement of parts is presently believed to be optimum, vari ations therefrom are'possible. For instance, the

spline ring might be mounted at that end of the hub which coincides with the apex of the coned disc; or one disc might be xed to the shaft While the other disc is mounted on the shaft in the manner illustrated, or is mounted upon a projecting, splined section of a hub carried by the fixed disc.

While the invention is deemed tc be of primary utility in the illustrated environment, it is by no means limited to that environment, but may be applied to any organization in which it is desired to provide an anti-friction, axial adjustment for an element having a driving connection with a shaft.

Throughout the present specification, and in the claims appended hereto, the term ball bushing is used to mean a unit of the type indicated herein by the reference numeral 33, and including a carrier providing a peripheral series of continuous trackways, each having an axially rectilinear section i, in which the balls project radially inwardly into supporting engagement with a shaft or the like, and a return section, such as 4i, peripherally spaced from the first-named axially rectilinear section in which the balls are held out of engagement with the element upon which the bushing is supported, the sections i5 and M being connected so that the balls may roll freely and continuously, in either direction, through a closed path.

I claim as my invention:

1. An expansible V-pulley mounting comprising a splined shaft, a coned disc mounted on said shaft to rotate therewith, and a mating coned disc mounted on said shaft to rotate therewith and for axial adjustment therealong relative -to said first-named disc, a ball bushing supporting said mating disc upon the splined region of said shaft, and means fixed with respect to said mating disc and interdigitated with the splined region of said shaft.

2. An expansible V-pulley mounting comprising a shaft provided with a peripheral series of spline teeth defined by spline grooves, a coned disc mounted on said shaft to rotate therewith, a mating coned disc, a ball bushing supporting said mating coned disc on said spline teeth, and means fixed with respect to said mating coned disc and slidably received in said spline grooves to provide a driving connection between said shaft and said mating coned disc.

3. An expansible V-pulley mounting comprising a shaft provided with a peripheral series of spline teeth defined by spline grooves, a coned disc mounted on said shaft to rotate therewith, a mating coned disc, said mating coned disc having an axially-elongated hub retreating from the apex of the coned face thereof, a ball bushing received within said hub and fixed against axial movement relative thereto, said bushing being supported on said spline teeth, and a toothed element xed to said hub at an end thereof and meshing with said spline grooves.

4. The assembly of claim 3 in which said toothed element is provided with a peripheral series of radially-inwardly directed teeth engaging in said spline grooves, the axial length of said teeth being substantially less than the axial length of said bushing.

5. `The assembly of claim 3 including a snapring received in said hub adjacent said apex and abutting one end of said bushing and in which said toothed element is removably fixed to the remote end of said hub and abuts the other end of said bushing. 6. An expansible V-pulley mounting comprising a splined shaft, a cooperating pair of coned discs mounted on said shaft, a ball bushing for each of said discs, each bushing being axially fixed relative to its disc and being supported upon the splined portion of said shaft, and other means fixed with respect to each disc and interdigitated with the splined portion of said shaft to provide a rotary driving connection between said shaft and its disc.

7. For association with a shaft provided with a peripheral series of spline teeth defined by spline grooves, a power-transmitting element having a hub, a ball bushing received in said hub and axially fixed relative thereto, said bushing being adapted to be supported on said spline teeth, and an element fixed to an end of said hub and provided with a peripheral series of radially-inwardly directed 'teeth adapted to mesh with said spline grooves.

8. The device of claim 7 in which each of said teeth of said element is axially substantially shorter than said bushing.

9. In combination, a splined shaft and a powertransmitting assembly mounted thereon for axial movement therealong, comprising a power-transmitting element having a hub, and a ball bushing received within said hub and supported on said shaft and comprising a carrier providing a peripheral series of continuous trackways, each having an axially rectilinear section and a return section peripherally spaced from said axially rectilinear section and connected to the latter to denne a continuous, closed path, and a series of balls received in each trackway, the balls in said axially rectilinear section of each trackway projecting radially inwardly into supporting engagement with a land of said splined shaft and the balls in said return section of each trackway being held radially out of engagement with said shaft, the balls in each trackway being free to roll continuously in either direction through the closed path defined by such trackway, said assembly including means providing a rotational driving connection between said shaft and said power-transmitting element.

JOHN S. MICHIE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name l Date 754,066 Hoffmann Mar. 3, e 851,728 Bayrer Apr. 30, 1907 1,375,053 Lewellen Apr. 19, 1921 2,371,330 Irstad Mar. 13, 1945 2,503,009 Thompson Apr. 4, 1950 FOREIGN PATENTS Number Country Date 862,230 France Mar. 1, 1941 

